In recent years, the range of use of LEDs has been widened rapidly, and the LEDs are used for headlights for automobiles. For the headlights, it is required to provide not only high-intensity light but also light having specific light distribution. In order to control light distribution, there is proposed a light emitting device in which side surfaces of an LED are coated with a light-reflective resin.
For example, Patent Document 1 describes a light emitting device including, as illustrated in FIGS. 14A and 14B: a substrate 51, on the upper surface of which wiring patterns 52 are provided; LEDs 53 mounted on two wiring patterns 52 with a predetermined clearance therebetween through flip-chip mounting to emit blue light; a translucent fluorescent plate 54 containing a fluorescent substance in abutment with the upper surfaces of the LEDs 53; a ZD 55 serving as a protective element mounted on two wiring patterns 52 with a predetermined clearance therebetween through flip-chip mounting; a frame-like dam material 56 that surrounds the LEDs 53 and the ZD 55; and a light-reflective resin 57 injected inside the dam material 56 to coat the side surfaces of the LEDs 53 and the side surfaces of the fluorescent plate 54 and coat the side surfaces and the upper surface of the ZD 55. The upper surface of the fluorescent plate 54, which serves as a light output surface, is not coated with the light-reflective resin 57 but exposed.
The blue light emitted from the LEDs 53 is exclusively output from the upper surfaces to enter the fluorescent plate 54 with components directed transversely from the side surfaces reflected and blocked by the light-reflective resin 57 and with components directed downward from the lower surfaces reflected and blocked by the wiring patterns 52. The blue light and fluorescent light emitted when the fluorescent substance contained in the fluorescent plate 54 is excited by the blue light are synthesized so that white light is output from the upper surface of the fluorescent plate 54.
A plurality of LEDs 53 is arranged in one row with a predetermined inter-chip distance therebetween. The single fluorescent plate 54 covers the plurality of LEDs 53, and has a rectangular shape as viewed in plan. The dam material 56 is provided at a predetermined separation distance from the fluorescent plate 54, and has a rectangular frame shape that is somewhat larger than the fluorescent plate 54 as viewed in plan. The height of the dam material 56 is larger than the height of the upper surface of the ZD 55, and equal to or less than the height of the upper surface of the fluorescent plate 54.
The ZD 55 is intended to protect the LED 53 from electrostatic breakdown, and mounted in parallel with and in the opposite direction to the LED 53. It is necessary that the ZD 55 should be blocked from the outside air or the like from the viewpoint of improving reliability. Therefore, the ZD 55 is disposed inside the dam material 56, and the side surfaces and the upper surface of the ZD 55 are coated with the light-reflective resin 57.